ASA 128th Meeting - Austin, Texas - 1994 Nov 28 .. Dec 02

2pPP1. Studies of the relationships between ear canal and cochlear signals for external tones and spontaneous and distortion product otoacoustic emissions, and their connection with middle ear transmission.

Carrick L. Talmadge

Arnold Tubis

Dept. of Phys., Purdue Univ., West Lafayette, IN 47907

Some knowledge about the transmission characteristics of the human middle ear may be obtained by comparing ear canal levels of external tones and spontaneous emissions of the same frequency, which when used with another tone give similar ear canal levels of distortion product otoacoustic emissions. It is assumed that the cochlear activity patterns of an external tone of frequency f2 and a spontaneous emission of frequency f2, which produce the same levels of ear canal cubic distortion products when used in conjunction with an external tone of frequency f1 and fixed level, are very similar. The degree of similarity is studied using nonlinear active cochlear models that give spontaneous emissions [Talmadge and Tubis (1993)]. The relationship of the cochlear activities at the place of peak excitation and at the base of the cochlea is also studied in detail. The model results indicate that the comparison of ear canal levels of external tones and spontaneous emissions, which are equivalent with respect to the production of distortion product emissions, may be used to give estimates of the reflection and transmission of cochlear waves at the stapes. [Work supported by the Deafness Research Foundation.]